1. Field of the Invention
This invention relates to a system and method for teaching physical skills and more particularly to a system and method for analyzing physical movement which require coordination in time, position of parts of the body, and movement of required equipment. It is adapted, among other possible applications, for use in improving a participant's skill in many activities such as sports and games, and is particularly applicable to golf.
2. Background Discussion
Throughout history, students have learned to perform a physical skill by watching and mimicking a teacher. For example in golf, players have looked to the best performers of the game for instruction. Professionals and amateurs alike regularly analyze the swings of elite golf performers for help with their own games. However, even when a golfer receives direct instructions from a professional teacher, the inability of the player to actually see his own performance frequently militates to slow down and limit improvement.
Attempts have been made to overcome this problem by the use of film, video equipment, and instant-development photography. Many efforts have been made, since the advent of photography, to devise systems for producing such images comparing the efforts of the student to a teacher. Several systems and methods have been proposed for producing the images described. These include McCollough U.S. Pat. No. 3,408,750, Snead U.S. Pat. No. 3,353,282 and Robertson U.S. Pat. No. 2,494,000. These systems, while useful, have certain disadvantages. McCollough requires a projection of a master image made by the student posed in proper positions for comparing the student's movements to the master image. Sneed requires the projection of a teacher's image on a mirror for comparing the student's movement. Robertson displays the image of a professional golfer for comparing the students's movements.
Three serious problems have continuously plagued these types of systems. The first problem involves the medium in which the the image presentation has been made. A typical video camera or film camera has such a long exposure time that any rapid movement by the participant in performing a physical skill produces a picture blur that makes visual explanation impossible. Second, the inability to superimpose or overwrite information on the video image severely limited this type of presentation. Third, the inappropriate comparison of the student to a teacher model with different body characteristics. For instance, comparing a student with a body height of 5'3" to a teacher with a height of 6'3". The golf swings are physically different between the student and teacher causing the student to compensate for the difference to learn the skill. This increases the complexity of learning the skill.
Advances in technology have solved the first and second problems. New solid state technology now provides high speed shuttered video cameras eliminating the blurring problem once found in capturing high speed motions on video tape. New computer image generation equipment now available allows video overlays.
However, the most serious problem involved the type of results to be presented. Although the previous systems attempted to overlay information on a video movement of a performer, the information must be specific to that performer to achieve satisfactory results. The usual type of overlay information systems employed consisted of either the student being positioned in a series of positions by a teacher while recording these positions or having the student compare himself to a teacher performing the required skill. Both cases resulted in unsatisfactory performance from the student. One problem is that the student must compare his performance to an image of a teacher that is not exactly the student's shape, weight, and size. The different physical dimensions between student and teacher results in different swings. Thus, a student was forced to make a comparison in swings that could be as different as apples and oranges. Another problem is that the teacher is usually not capable of superiorly performing the physical skill. Since it is extremely unlikely that a student will have the same physical characteristics as a teacher and that a teacher had the perfect swing the previous systems were rendered ineffective.
This problem has been solved with the advent of high speed general purpose computers and recent advances in biomechanical science. The combination of biomechanics and computers has led in recent years to computer modeling of human motion.
Complex models ranging from multi-segment skeletal systems to full humanoid models are now possible. The only limitation to representing human motion with computer models lies in computer power and time required to draw the model. The major biomechanical problem is that of generating the proper computer model for performance comparisons. There are two requirements that are critical if any valid comparisons are to be made. The first requirement is that the computer generated performance must be superior to the human performance to which it is being compared. The second requirement is that the computer generated performance be within the reach of human capabilities. Since the computer is not bound by the physiological limitations of the human body, it can have its creation performed feats that no human can match. Fifty feet long jumps, 30-foot high jumps, anything is possible if no restrictions are placed on the computer generated performance.
The solution to this problem is to generate a performer with the same physical characteristics as the student, having superior movement patterns but constrained to human capabilities. The only way to accomplish this is to create this model performer using computer and graphic techniques. Using this approach entails solving a number of problems. The first involves the visual quality of the computer generated performance, since a simplistic body representation cannot portray true body positions sufficiently to effectively make comparisons. This problem is solved with development of increasingly complex humanoid representation capabilities.